Amidoamines are well-known raw materials used as conditioning agents in the cosmetic and personal care products and conform to the following structure:
At the extremes of the pH range, amidoamines are non-protonated.
Shea butter is a butter extracted from the kernel of Butrospermum parkii. This plant, also referred to as Vitellaria paradoxa, is native to Africa. The term butter describes a material that is a solid at room temperature, but melts at about 40° C. Chemically, shea butter is a triglyceride conforming to the following structure:
wherein R1, R2 and R3 each have one of the following compositions:
R GroupCommon NameRange (%)Typical (%)C11H23Lauryl0.1–2.00.2C13H27Myristyl0.5–2.01.0C15H31Cetyl2.0–6.04.0C17H35Stearyl25.0–50.035.0 C17H33Oleyl40.0–60.059.0 C17H31Linoleyl0.5–1.00.8
The average composition of R2 is different than R1 and R3, the latter two being similar. The R2 moiety contains predominantly the unsaturated C18 group (oleyl) while R1 and R3 contain predominantly the saturated C18 group (stearyl). Differences between internal (R2) and terminal (R1, R3) substitution are seen in natural products but not in synthetic molecules produced in the laboratory.
The high levels of stearyl and oleyl groups make shea butter and its DMAPA derivatives of particular interest in the personal care industry. While other raw materials used in personal care products have these species, the compounds of the present invention have significantly high concentrations of unsaponifiables, which posses highly desired antioxidant, ultra-violet radiation protection, and free-radical scavenging properties. Mild-processed shea butter typically contains from about 5% to about 15% by weight of unsaponifiables. In contrast, other butters commonly used in personal care products have less than 2% unsaponifiables. For example, coca butter (from Theobroma cacao) averages 0.4% unsaponifiables and Illipe butter (from Shorea stenoptera) averages 1.1%.
As described in greater detail below, the novel shea butter DMAPA compounds of the present invention are produced by reacting shea butter, preferably MPSB, with DMAPA, preferably under specific mild processing conditions. By “mild processed” is meant processes that do not remove or otherwise diminish the amount or potency of active ingredients, particularly highly desired unsaponifiables, from the mild-processed shea butter. In one aspect of the present invention, mild processing is employed both at the time of harvesting and initial extraction and during subsequent preparation of derivatives. These mild processes result in materials containing unexpectedly high amounts unsaponifiables, notably antioxidants.
U.S. Pat. No. 5,741,915 discloses betaine compounds based on meadowfoam, including the use of meadowfoam amidopropyl dialkyl amine intermediate in the preparation of meadowfoam-based betaines. While providing conditioning properties, the materials described in the '915 patent do not possess the desirable unsaponifiable fractions, and with them antioxidant properties, of the compounds of the present invention.
The shea butter DMAPA derivatives of the present invention thus deliver unexpectedly high amounts of unsaponifiables containing antioxidants to the skin and hair in a heretofore unachievable manner.